Nicola Sturgeon has not ruled out bringing in testing for primary-school pupils as she said she was determined to improve Scotland's education system.

The SNP leader came under fire on her Government's record on education, with Labour, the Tories and the Liberal Democrats all pressing her on the issue at First Minister's Questions.

A recent survey of literacy and numeracy found there had been a drop in standards in both reading and writing, and Education Secretary Angela Constance said earlier this week some children are ''failed by school''.

Conservative leader Ruth Davidson said there was a need for a "new system of primary testing" such as there is in Denmark and Ontario, "so that we all can see which schools need help and which schools are leading the way".

Ms Davidson said: "After eight years of this government, until your child is 14 years old, you have no clear idea how good their education is in comparison to the rest of the country.

"It is no wonder that the Scottish Government doesn't know what to do because it doesn't know what is going on."

She asked the First Minister: "Enough is enough, will you get on and introduce primary testing or not?"

Ms Sturgeon told her: "I openly acknowledge that while we do have, through exam passes, a wealth of data about the performance of secondary-school pupils, we do not have that same data on primary-school pupils."

She said there was a "serious and substantial" programme of work under way, adding: "I'm not going to simply give Ruth Davidson a yes or a no answer, to jump to the decisions before we have properly considered what the right thing to do is.

"We do need a new national performance framework, but we do need to make sure that the data we're collecting and the way we do that is right, proportionate and sensible.

"We're considering these issues at the moment and I look forward, and the Education Secretary looks forward, to updating Parliament very soon on the the direction in which we want to go."

Ms Sturgeon added: "I am determined that we make the improvements in our education system that require to be made.

"I, with Angela Constance, with the entire government, are going to roll up our sleeves and do the hard work that needs to be done to do right by the young people of Scotland."

Ms Sturgeon said while it was "not true to say things are not going in the right direction" in Scottish education, there are still "improvements that require to be made".

She told the Tory leader the Scottish Government was working on a new national performance framework.

That is being done "because I don't mind admitting a frustration that I can stand here and I can give detail on the performance of secondary-school pupils in terms of exam passes, it's much more difficult to do that in terms of the performance of primary-school pupils because of a lack of data", Ms Sturgeon said.

"That's something I want to address, I want to address that in a serious, proportionate and well thought-out way.

"That is the work that is under way in the Scottish Government and Parliament, of course, will be kept fully updated."

The Scottish Tory leader called for the reintroduction of primary testing after Labour's Kezia Dugdale had challenged Ms Sturgeon on the SNP's record on further and higher education.

Ms Dugdale, Scottish Labour's deputy leader, said since the nationalists came to power in 2007 "bursaries and grants for students have been slashed by £40 million" while "average debt per student has doubled under the SNP".

Ms Sturgeon insisted financial support for students in Scotland "stands comparison with that of other parts of the UK" as she added that those studying north of the border had lower student loan debts.

She said: "No issue is more important to me and no issue is more important to this government than our education system.

"I will not hold back from being open about where improvements are needed, but equally I will not hold back from challenging those who seek to paint an inaccurate picture of Scottish education, because I think that does a disservice to the achievements of young people and children across the country."

The First Minister also criticised Ms Dugdale for raising the issue of student debt.

"For the party that introduced tuition fees in Scotland, for the party that broke a manifesto commitment to introduce tuition fees in England, for a party that broke a manifesto commitment not to introduce top-up tuition fees to do precisely that, I think it is sheer and utter hypocrisy for Labour to come to this chamber and talk about student debt," Ms Sturgeon said.

Ms Dugdale argued it was her party that had scrapped tuition fees in Scotland.

"It was the Labour Party that abolished tuition fees in 2001," she said.

"I say that to the First Minister in the most sincere way because I was at university when this Labour Party abolished fees."

Ms Sturgeon responded: "Can I say to Kezia Dugdale just because she says something in a sincere way doesn't make it true.

"Labour removed tuition fees from the front end of education and put them at the back end of education, that's not abolishing tuition fees."

She added: "I know Labour lives in a parallel universe these days and who can blame them, because the real universe for Scottish Labour is a pretty miserable place to be. But trying to pretend they abolished tuition fees really takes the biscuit.

"Perhaps it is insulting the intelligence of the Scottish people in that way that has resulted in Labour being in the dire position it is in today."

Liberal Democrat leader Willie Rennie also challenged the First Minister on education as he urged Ms Sturgeon to introduce the "pupil premium" in Scotland.

The additional funding is given out by the UK Government to schools in England to raise attainment among disadvantaged students.

"Our proposals on the pupil premium have been repeatedly dismissed as unnecessary by successive education ministers, happy to argue that everything is fine," Mr Rennie said.

"In England, the pupil premium has closed the gap in attainment for primary-school children.

"It allows for one-to-one tuition, books, equipment and targeted support that children from disadvantaged backgrounds need."

Mr Rennie said the Scottish Government's attainment fund only covers seven local authorities while the pupil premium would be for the whole country.

"Will the First Minister finally just agree that the pupil premium closes the gap in attainment and it should be introduced in Scotland?" Mr Rennie asked.

Ms Sturgeon said: "A £100 million attainment fund focused on the local authorities where I think everybody accepts the biggest concentrations of people living in our most deprived communities are - it may be some of that money goes to other local authorities where there are clusters of deprivation in particular areas.

"But surely it is right that having set aside that substantial financial investment, to make sure that investment is being focused exactly where it is needed most so that we can drill down on where the issues are, and make sure we have that rigorous approach in place to making improvements and monitoring improvements."

She said the government would not "close is mind" to ideas brought forward, but would get on with implementing its "serious and substantial" programme of improvements.